I Could Never Get a Definitive Yes/No Answer on This One...

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Quartz_Lock10729
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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Quartz_Lock10729 » 23 Apr 2018 21:38

toaster999 wrote:
Quartz_Lock10729 wrote:When switching out a cartridge for a replacement/new one, does the tonearm HAVE to be rebalanced doing the whole balancing/zero weight routine if using a digital scale to measure VTF?

yes.
Why?

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Quartz_Lock10729 » 23 Apr 2018 21:43

nat wrote:Is the scale you are using at the same height as the record surface? Most arms do not have the vertical bearings at the same height as the record, so unless the scale platform is at the record height, it will read incorrectly - think about the geometry, where the arm moves in an arc, which, with most bearings, will move the stylus backwards (based on a line perpendicular to the record surface) when placed on a scale that is higher than the record. At the same time, the counterweight is moving, in the same way, closer to the bearings. So the reading will be wrong.
We went over this in a different thread, and I was assured by some very knowledgeable people on this forum that if I'm using a tonearm with a counterweight such as the one my AT-LP120-USB utilizes, the scale reading can be taken at the height of the platter mat (which I have been doing).

But that's not even the point of this particular thread...
Companies capable of designing and manufacturing turntables on an on going basis are usually completely capable of working out the geometry of moving systems, and of how to get a simple spiral thread to correlate with the markings on a bezel. As someone who was an obsessive reader of equipment reviews in the 70s and 80s, I can say confidently that almost never was the tracking force scale off by more than 10 percent. Of course this was with experienced technical staff, which not all subsequent reviewers, especially on the internet, are.
I do not understand the mindset that is convinced that a cheap ten buck scale employed any which way is obviously superior to fine mechanical scales used by professionals with long experience in the field, but apparently if it is digital, that is all that matters.
I'm only going by what MY Hanpin-sourced turntable's counterweight markings showed me...the digital scale, placed around LP height on the platter mat, was significantly off when I thought I was at 2.0 grams initially...

At any rate, what I wanted to know by posting this thread is this:

If I'm using a DIGITAL SCALE to confirm VTF, do I have to rebalance the arm and zero out the counterweight from the beginning if I'm using a new cartridge, or can I simply install the new cartridge on the headshell and begin verifying VTF (and adjusting anti skate) with the digital scale? The arm doesn't have to be re-floated if I'm using an outboard scale to verify tracking weight, does it?

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by JoeE SP9 » 23 Apr 2018 22:35

NO! :mrgreen:

Japi Roelofs
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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Japi Roelofs » 24 Apr 2018 10:31

Let's assume you have a 5 gram cartridge on your tonearm, that needs 2 grams of tracking force. You set the tracking force using a digital scale.

Now let's assume you want to change the cartridge, and the new one is a 10 gram cartridge, that also needs 2 grams of tracking force. If you don't change the position of the counterweight, and just put on the new cartridge and put it on the digital scale, what force is going to be put on the stylus / cantilever / suspension?

I don't know how to do the math, but you can imagine the tracking force is now way too high, and this might damage the cartridge suspension.

This would be the only reason to re-balance the tonearm, prior to using the digital scale. If it was the other way around (original cart 10 gram, new cart 5 gram) there would be no problem of course.

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by cafe latte » 24 Apr 2018 12:09

smee4 wrote:Cartridges don't all weigh the same amount, so yes, you need to adjust the tracking force, but, sure, you can choose to ignore the the dial on the tonearm and any precious setting. Just plug in the new cartridge/headshell, align it properly using a protractor, then set the vtf using the digital scale.
Digital scales are no more accurate than the arm being zeroed ie floating and then dialing ion the new weight. Digital scales that cost 50 bucks are not that accurate at all really. I shoot FTR long range ie 1km and my powder scales (digital) cost around 1,000 dollars as the 250 dollar ones just were not accurate enough. Stylus dont need serious accuracy, that said all you gain from a 50 dollar stylus scale is readings that are digital not accurate and if the battery is dead you get nothing why I bought a stylus beam scale it always works (only used for my Eminent arm which has no dial in).
Chris

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by smee4 » 24 Apr 2018 12:40

cafe latte wrote:I shoot FTR long range ie 1km and my powder scales (digital) cost around 1,000 dollars as the 250 dollar ones just were not accurate enough. Stylus dont need serious accuracy, that said all you gain from a 50 dollar stylus scale is readings that are digital not accurate

and yet calibration weights placed on the scale read the correct values.

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by cafe latte » 24 Apr 2018 13:09

smee4 wrote:
cafe latte wrote:I shoot FTR long range ie 1km and my powder scales (digital) cost around 1,000 dollars as the 250 dollar ones just were not accurate enough. Stylus dont need serious accuracy, that said all you gain from a 50 dollar stylus scale is readings that are digital not accurate

and yet calibration weights placed on the scale read the correct values.
But are the scales linear? This is the issue the scale measures the calibration weights ie 1 and 5g but does it measure 1.5g accurately? And is it accurate after 10 minutes? Unlikely with strain gauge scales which is why I invested 1k on scales which use magnetic resonance not strain gauge.
Chris

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by duficity » 24 Apr 2018 13:31

Chris,
Still using the et2 I see. Have you got it dialed in? which cartridge are you using on it?

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Audie » 24 Apr 2018 19:03

Quartz-Lock, I think you should do the full setup procedure - It will get you in the ballpark.
You will need adjustable VTA, as VTA/SRA will be important with the microline stylus profile cartridge you intend to use.
The more revealing the system, the more apparent the stylus alignment will be.

Audie

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by feldman » 24 Apr 2018 19:22

Quartz_Lock10729 wrote:When switching out a cartridge for a replacement/new one, does the tonearm HAVE to be rebalanced doing the whole balancing/zero weight routine if using a digital scale to measure VTF?

In other words, when I eventually get a microline cart and stylus to replace my AT95e with, do I have to rebalance the tonearm of my LP120 if I'm using a digital scale to measure the tracking force, or can I simply plug in the headshell with the new cart and dial in VTF (and AS) for the new cart's specs? I don't have to "zero out" the arm again if I'm using a digital scale, right?
At the end of the day, when the record is spinning and the stylus is tracking the grooves, all that matters is the VTF that is measurable at that point. How you arrived at that particular VTF is totally irrelevant.

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by feldman » 24 Apr 2018 19:26

cafe latte wrote:
smee4 wrote:
cafe latte wrote:I shoot FTR long range ie 1km and my powder scales (digital) cost around 1,000 dollars as the 250 dollar ones just were not accurate enough. Stylus dont need serious accuracy, that said all you gain from a 50 dollar stylus scale is readings that are digital not accurate

and yet calibration weights placed on the scale read the correct values.
But are the scales linear? This is the issue the scale measures the calibration weights ie 1 and 5g but does it measure 1.5g accurately? And is it accurate after 10 minutes? Unlikely with strain gauge scales which is why I invested 1k on scales which use magnetic resonance not strain gauge.
Chris
That's an urban myth. My electronic scale comes with a weight measuring 5 grams. It ALWAYS measures 5 grams, no matter how many times I do it in a row. Plus, that weight measures exactly 5 grams if I take it to the lab and measure it with professional grade equipment. So I don't see how could electronic scales be incorrect, within the 0.01 gram of error margin? All that keeping in mind that exact VTF is not a life-or-death matter.

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Quartz_Lock10729 » 24 Apr 2018 19:36

Japi Roelofs wrote:Let's assume you have a 5 gram cartridge on your tonearm, that needs 2 grams of tracking force. You set the tracking force using a digital scale.

Now let's assume you want to change the cartridge, and the new one is a 10 gram cartridge, that also needs 2 grams of tracking force. If you don't change the position of the counterweight, and just put on the new cartridge and put it on the digital scale, what force is going to be put on the stylus / cantilever / suspension?

I don't know how to do the math, but you can imagine the tracking force is now way too high, and this might damage the cartridge suspension.

This would be the only reason to re-balance the tonearm, prior to using the digital scale. If it was the other way around (original cart 10 gram, new cart 5 gram) there would be no problem of course.
I understand what you're saying, but that's precisely why I stated I would begin the process by dialing my counterweight way back to make it much lighter in downforce to begin the measurements of the new cart (which is definitely going to track lighter than the one I'm using now).

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Quartz_Lock10729 » 24 Apr 2018 19:37

JoeE SP9 wrote:NO! :mrgreen:
Thanks...but are you being serious, Joe, based on my concern?

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Quartz_Lock10729 » 24 Apr 2018 19:39

Audie wrote:Quartz-Lock, I think you should do the full setup procedure - It will get you in the ballpark.
You will need adjustable VTA, as VTA/SRA will be important with the microline stylus profile cartridge you intend to use.
The more revealing the system, the more apparent the stylus alignment will be.

Audie
Audie,

My counterweight readings already proved that they're not accurate from the Hanpin factory. That's why I want to skip going through the arm balance routine if I can and straight to using the digital scale when I get a new cart -- my question, again, is: Do I HAVE to rebalance the arm and set the counterweight ring to read "0" when the arm is floating IF I plan on using a digital scale anyway for final VTF measurements?

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Re: I Could Never Get a Definitive Yes/No Answer on This One

Post by Quartz_Lock10729 » 24 Apr 2018 19:41

feldman wrote:
Quartz_Lock10729 wrote:When switching out a cartridge for a replacement/new one, does the tonearm HAVE to be rebalanced doing the whole balancing/zero weight routine if using a digital scale to measure VTF?

In other words, when I eventually get a microline cart and stylus to replace my AT95e with, do I have to rebalance the tonearm of my LP120 if I'm using a digital scale to measure the tracking force, or can I simply plug in the headshell with the new cart and dial in VTF (and AS) for the new cart's specs? I don't have to "zero out" the arm again if I'm using a digital scale, right?
At the end of the day, when the record is spinning and the stylus is tracking the grooves, all that matters is the VTF that is measurable at that point. How you arrived at that particular VTF is totally irrelevant.
Thank you; so by skipping the balancing routine, this doesn't mean something is actually being "left out" IF I'm measuring the downforce with a digital scale, right?

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